diff --git a/apps/desktop/src/index.css b/apps/desktop/src/index.css
index 879898e..244ef4d 100644
--- a/apps/desktop/src/index.css
+++ b/apps/desktop/src/index.css
@@ -21,7 +21,7 @@ body {
 }
 
 .btn {
-  @apply inline-flex items-center justify-center rounded-lg border px-3 py-2 text-sm font-semibold transition;
+  @apply inline-flex items-center justify-center rounded-md border px-3 py-2 text-sm font-semibold transition;
 }
 
 .btn-primary {
@@ -49,7 +49,7 @@ body {
 }
 
 .tab-btn {
-  @apply rounded-lg border border-transparent bg-transparent px-3 py-1.5 text-sm font-medium text-slate-700 hover:bg-slate-100;
+  @apply rounded-md border border-transparent bg-transparent px-3 py-1.5 text-sm font-medium text-slate-700 hover:bg-slate-100;
 }
 
 .tab-btn.active {
diff --git a/src/app/api/machines/session/route.ts b/src/app/api/machines/session/route.ts
index a6412d0..790f70f 100644
--- a/src/app/api/machines/session/route.ts
+++ b/src/app/api/machines/session/route.ts
@@ -6,6 +6,7 @@ import { api } from "@/convex/_generated/api"
 import type { Id } from "@/convex/_generated/dataModel"
 import { env } from "@/lib/env"
 import { assertAuthenticatedSession } from "@/lib/auth-server"
+import { DEFAULT_TENANT_ID } from "@/lib/constants"
 
 const MACHINE_CTX_COOKIE = "machine_ctx"
 
@@ -88,17 +89,56 @@ export async function GET(request: NextRequest) {
       authEmail: string | null
     }
 
+    let ensuredAssignedUserId = context.assignedUserId
+    let ensuredAssignedUserName = context.assignedUserName
+    let ensuredAssignedUserRole = context.assignedUserRole
+
+    if (!ensuredAssignedUserId && context.persona && context.assignedUserEmail) {
+      try {
+        const ensuredUser = (await client.mutation(api.users.ensureUser, {
+          tenantId: context.tenantId ?? DEFAULT_TENANT_ID,
+          email: context.assignedUserEmail,
+          name: context.assignedUserName ?? context.assignedUserEmail,
+          avatarUrl: undefined,
+          role: (context.assignedUserRole ?? context.persona ?? "collaborator").toUpperCase(),
+          companyId: context.companyId ?? undefined,
+        })) as { _id?: Id<"users">; name?: string | null; role?: string | null } | null
+
+        if (ensuredUser?._id) {
+          ensuredAssignedUserId = ensuredUser._id as string
+          ensuredAssignedUserName = ensuredUser.name ?? context.assignedUserName
+          ensuredAssignedUserRole = ensuredUser.role ?? context.assignedUserRole
+
+          await client.mutation(api.machines.updatePersona, {
+            machineId: machineId as Id<"machines">,
+            persona: context.persona ?? undefined,
+            assignedUserId: ensuredUser._id as Id<"users">,
+            assignedUserEmail: context.assignedUserEmail,
+            assignedUserName: ensuredAssignedUserName ?? undefined,
+            assignedUserRole: (ensuredAssignedUserRole ?? context.persona ?? "collaborator").toUpperCase(),
+          })
+        }
+      } catch (error) {
+        console.error("[machines.session] Falha ao garantir usuário vinculado", error)
+      }
+    }
+
     const responsePayload = {
       machineId: context.id,
       persona: context.persona,
-      assignedUserId: context.assignedUserId,
+      assignedUserId: ensuredAssignedUserId,
       assignedUserEmail: context.assignedUserEmail,
-      assignedUserName: context.assignedUserName,
-      assignedUserRole: context.assignedUserRole,
+      assignedUserName: ensuredAssignedUserName,
+      assignedUserRole: ensuredAssignedUserRole,
     }
 
     const response = NextResponse.json({
-      machine: context,
+      machine: {
+        ...context,
+        assignedUserId: ensuredAssignedUserId ?? null,
+        assignedUserName: ensuredAssignedUserName ?? null,
+        assignedUserRole: ensuredAssignedUserRole ?? null,
+      },
       cookie: responsePayload,
     })
 
diff --git a/src/components/portal/portal-shell.tsx b/src/components/portal/portal-shell.tsx
index 2b937e1..07462a3 100644
--- a/src/components/portal/portal-shell.tsx
+++ b/src/components/portal/portal-shell.tsx
@@ -79,7 +79,7 @@ export function PortalShell({ children }: PortalShellProps) {
               <GalleryVerticalEnd className="size-4" />
             </span>
             <div className="flex flex-col">
-              <span className="text-xs font-semibold tracking-[0.04em] text-neutral-500 sm:tracking-[0.06em]">
+              <span className="text-sm text-neutral-500">
                 Portal do Cliente
               </span>
               <span className="text-lg font-semibold text-neutral-900">Raven</span>
diff --git a/src/components/portal/portal-ticket-form.tsx b/src/components/portal/portal-ticket-form.tsx
index d4f597f..2cbe0bb 100644
--- a/src/components/portal/portal-ticket-form.tsx
+++ b/src/components/portal/portal-ticket-form.tsx
@@ -48,10 +48,18 @@ export function PortalTicketForm() {
   const isFormValid = useMemo(() => {
     return Boolean(subject.trim() && description.trim() && categoryId && subcategoryId)
   }, [subject, description, categoryId, subcategoryId])
+  const isViewerReady = Boolean(viewerId)
 
   async function handleSubmit(event: React.FormEvent) {
     event.preventDefault()
-    if (!viewerId || !isFormValid || isSubmitting) return
+    if (isSubmitting || !isFormValid) return
+    if (!viewerId) {
+      toast.error(
+        "Não foi possível identificar o colaborador vinculado a esta máquina. Tente abrir novamente o portal ou contate o suporte.",
+        { id: "portal-new-ticket" }
+      )
+      return
+    }
 
     const trimmedSubject = subject.trim()
     const trimmedSummary = summary.trim()
@@ -113,6 +121,11 @@ export function PortalTicketForm() {
         <CardTitle className="text-xl font-semibold text-neutral-900">Abrir novo chamado</CardTitle>
       </CardHeader>
       <CardContent className="space-y-6 px-5 pb-6">
+        {!isViewerReady ? (
+          <div className="rounded-xl border border-amber-200 bg-amber-50 px-4 py-3 text-sm text-amber-700">
+            Vincule esta máquina a um colaborador na aplicação desktop para enviar chamados em nome dele.
+          </div>
+        ) : null}
         <form onSubmit={handleSubmit} className="space-y-6">
           <div className="space-y-3">
             <div className="space-y-1">
@@ -186,7 +199,7 @@ export function PortalTicketForm() {
             </Button>
             <Button
               type="submit"
-              disabled={!isFormValid || isSubmitting || !viewerId}
+              disabled={!isFormValid || isSubmitting}
               className="rounded-full bg-neutral-900 px-6 text-sm font-semibold text-white hover:bg-neutral-900/90"
             >
               Registrar chamado